This application claims the benefit of and priority from Japanese Application No. 2001-98088 filed Mar. 30, 2001, the content of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a tank cap, having a torque mechanism for closing the opening of a tank with a predetermined rotational torque.
2. Description of the Related Art
One example of known tank caps is described in JP No. 2000-344266A. As shown in FIG. 15, a fuel cap 100 comprises a casing main body 110, a handle 120, and a torque mechanism 130. The torque mechanism 130 comprises handle engagement elements 122 formed on the handle 120, a torque plate 140 having torque piece engagement elements 142, and a spring 132. When the handle 120 is rotated in the closing direction, the handle engagement elements 122 engage with the torque piece engagement elements 142 and disengage with the torque piece engagement elements 142, giving the user a feeling of attachment by an audible click (first non-engaged state). At this time, the spring accumulates the pressing force applied in the opening direction.
The pressing force accumulated in the spring causes the handle engagement elements 122 to disengage with the torque piece engagement elements 142 with a small rotational torque (second non-engaged state). The handle 120 returns to an initial position relative to the casing main body 110.
However, in the conventional the fuel cap 100, the rotational torque for the handle engagement, element 122 to disengage torque piece engagement elements 142 is large. The rotational torque is particularly large when transitioning to the second non-engaged state, resulting in the problem of a large noise, which is hard on the ears, being caused by the operation.
The object of the present invention is thus to provide a tank cap which can close a tank opening with a small value of rotating, has outstanding operability such as in regard to alignment for opening and closing, and also has reduced operating noise during opening and closing.
At least part of the above and the other related objects are obtained by a tank cap configured to open and close a tank opening and to engage with an opening engagement element disposed on a circumference of the tank opening.
The tank cap comprises a casing main body for sealing the tank opening, the casing main body including a casing engagement element configured to engage with the opening engagement element via rotation of the casing main body by a predetermined angle; a handle rotatably mounted on the casing main body; and a torque mechanism interposed between the handle and the casing main body, the torque mechanism including (i) a handle engagement element disposed on a lower portion of the handle and (ii) an elastic torque piece with a torque piece engagement element engaging wish the handle engagement element, the elastic torque piece configured to transmit rotational torque applied to the handle to the casing main body via engagement between the handle engagement element and the torque piece engagement.
The torque piece engagement element is configured to be selectively put one of in an engagement state, a first non-engaged state, and a second non-engaged state. In the engagement state, the torque piece engagement element engages with the handle engagement element so that the rotational torque applied to the handle is transmitted to the casing main body via the elastic torque piece when the handle is rotated in a closing direction of the tank opening. In the first non-engaged state, the torque piece engagement element is released from the handle engagement element with a first force due to a first rotational torque when the torque piece engagement element engages with the handle engagement element, and then the handle is rotated in the closing direction of the tank opening. In the second non-engaged state after being in the first non-engaged state, the torque piece engagement element is released from the handle engagement element with a second force due to a second rotational torque when the torque piece engagement element engages with the handle engagement element, and then the handle is rotated in the opening direction of the tank opening, a direction of the second force being different from that of the first force, and the second force being less than the first force.
With the tank cap of the present invention, when the handle is rotated in the closing direction, aligning the casing engagement element of the casing main body to the opening engagement element of the tank opening, the casing main body, via the torque mechanism, rotates as a unit with the handle and the casing engagement element engages the opening engagement element. At this time, when the torque piece engagement element of the torque mechanism goes into the engaged state where it engages with the handle engagement element of the handle, the rotational torque applied to the handle is transmitted to the casing main body. When the rotational torque exceeds a predetermined value and the torque piece engagement element disengages with the handle engagement element to change the first non-engaged state, the user can receives a feeling of attachment by an audible click and confirms that the cap has been closed with the predetermined torque.
On the other hand, in the state where the tank cap has closed the tank opening, when the rotational torque is applied to the handle in the opening direction, the handle engagement element and torque piece engagement element go into the second non-engaged state to disengage by means of a smaller torque than with the first non-engaged state. That is, the rotating force in the closing direction returns the positional relationship between the handle engagement element and the torque piece engagement element to an initial position. Thus, when the tank cap is to be closed again, the positional relationship of the torque piece engagement element and handle engagement element is fixed and alignment for closing the tank opening is facilitated.
Since the elastic deformation direction of the elastic torque piece is a different direction for first non-engaged state and for second non-engaged state, the cap allows a greater degree of freedom. For example, the torque mechanism can be easily designed such that the elastic torque piece has the elastic deformation of second non-engaged state markedly smaller than that of the first non-engaged state.
In accordance with a preferred embodiment of the present invention, the torque mechanism comprises a torque plate interposed between the handle and the casing main body.
In accordance with another preferred embodiment of the present invention, the torque mechanism is configured that the first force is applied to the torque piece engagement element from a radial direction relative to an axial direction of the tank cap, and the second force is applied to the torque piece engagement element from the axial direction.
In accordance with still another preferred embodiment of the present invention, the handle engagement element includes a first engaging vertical surface, and the torque piece engagement element includes an engaging vertical surface conforming to the engaging vertical surface, the elastic torque piece being configured to deform by the first force when the handle is rotated in the closing direction, and wherein the handle engagement element includes an engaging inclined surface inclined by a predetermined angle relative to the axial direction, and the torque piece engagement element includes an engaging inclined surface conforming to the engaging inclined surface, the elastic torque piece being configured to deform by the second force when the handle is rotated in the opening direction.
In accordance with another preferred embodiment of the present invention, wherein the elastic torque piece is a cantilevered piece, the cantilevered piece being configured to deform more significantly in the second non-engaged state than in the first non-engaged state when the torque piece engagement element is pressed against the handle engagement element.
In accordance with still another preferred embodiment of the present invention, the torque mechanism includes a torque plate interposed between the handle and the casing main body, the elastic torque piece having the torque piece engagement element.
In accordance with another preferred embodiment of the present invention, the torque mechanism further comprises a spring, the spring generating a pressing force to return a positional relationship between the handle and the casing main body to an initial state.
In accordance with another preferred embodiment of the present invention, the spring is a coil spring that accumulates the pressing force when being twisted.
In accordance with another preferred embodiment of the present invention, the spring is interposed between the handle and the torque plate, the spring accumulating the pressing force in response to a rotation of the handle in the opening direction of the tank opening, the pressing force accumulated in the spring being released so that the first non-engaged state is changed to the second non-engaged state.
In accordance with another preferred embodiment of the present invention, the spring is interposed between the casing main body and the torque plate, the spring accumulating the pressing force in response to a rotation of the handle in the closing direction of the tank opening, the pressing force accumulated in the spring being released so that the second non-engaged state is changed to the initial state.
In accordance with another preferred embodiment of the present invention, the elastic torque piece is integrally formed on the casing main body.
In accordance with another preferred embodiment of the present invention, the elastic torque piece includes a leg projecting from an upper portion of the casing main body and a cantilevered arm integrally formed with an upper portion of the leg, the cantilevered arm being disposed to have a gap between the cantilevered arm and the casing main body.
In accordance with another preferred embodiment of the present invention, the tank opening is a fuel supply inlet of a fuel tank mounted on an automobile.
The present invention is also directed to a tank cap configured to open and close a tank opening and to engage with an opening engagement element disposed on a circumference of the tank opening, the tank cap comprises a casing main body for sealing the tank opening, the casing main body including a casing engagement element configured to engage with the opening engagement element via rotation of the casing main body by a predetermined angle;
a handle rotatably mounted on the casing main body; and
a torque mechanism interposed between the handle and the casing main body, the torque mechanism including (i) a handle engagement element disposed on a lower portion of the handle and (ii) an elastic torque piece with a torque piece engagement element engaging with the handle engagement element, the elastic torque piece configured to transmit rotational torque applied to the handle to the casing main body,
wherein, when a first rotational force is applied to the handle by a user in a first rotational direction in order to attach the casing main body in the tank opening, the handle engagement element engages with the torque piece engagement element, and then the elastic torque piece is deformed to release the engagement between the handle engagement element and the torque piece engagement element when the first rotational force causes a first stress exceeding a first value between the handle engagement element and the torque piece engagement element, and wherein, when a second rotational force is applied to the handle in a second rotational direction opposite from the first rotational direction, the handle engagement element engages with the torque piece engagement element, and then the elastic torque piece is deformed to release the engagement between the handle engagement element and the torque piece engagement element when the second rotational force causes a second stress exceeding a second value between the handle engagement element and the torque piece engagement element, the second value being less than the first value, and the direction of the first stress being different from that of the second stress.